1. Field of the Invention
The present invention relates to a living-body observation system which can acquire information in a living body by means of an in-vivo observation apparatus, and a driving method of the living-body observation system.
2. Description of Related Art
Conventionally, endoscopes have been widely used in the medical field and others. In particular, endoscopes in the medical field are mainly used for the purpose of observing the inside of a living body. A capsule endoscope is proposed in recent years, as one type of the endoscopes described above, which is introduced into a body cavity by being swallowed by an examinee, and is capable of picking up images of inside the body cavity while being moved in the body cavity according to peristaltic movement, and wirelessly transmitting the picked-up images of inside the body cavity to outside as image pickup signals.
The capsule endoscopes which, as described above, moves in a body cavity while picking up images of inside the body cavity, include a type in which the number of images of inside a body cavity picked up in one second, that is, a frame rate is constant, and a type in which the frame rate is changed depending on the site to be observed.
Conventional capsule endoscopes in which the frame rate is changeable include, for example, a capsule endoscope proposed in Japanese Patent Application Laid-Open Publication No. 2005-193066. FIG. 12 is a longitudinal sectional view to schematically show the capsule endoscope disclosed in Japanese Patent Application Laid-Open Publication No. 2005-193066. Moreover, FIG. 13 is an explanatory diagram for use of the capsule endoscope of FIG. 12.
Japanese Patent Application Laid-Open Publication No. 2005-193066 discloses, as shown in FIG. 12, a technology relating to a capsule endoscope which is configured to accommodate an image pickup device 101, illumination means 102, an image signal processing circuit 103, a memory 104, an image information transmission circuit 105, a battery 106, a transmission antenna 107, and position detection means 108 in an endoscope capsule body 99 of a capsule endoscope 100 so that the position of the capsule endoscope 100 itself which moves in a body cavity is detected by the position detection means 108.
The capsule endoscope 100 according to Japanese Patent Application Laid-Open Publication No. 2005-193066 requires that an external body plate 109 made up of a magnetic plate, a conductive plate, or a magnetic coil, etc. is placed to the body of the examinee as shown in FIG. 13, to detect the position of the capsule endoscope 100 itself. It is noted that the use example shown in FIG. 13 shows a case in which the external body plate 109 is placed along the esophagus 121 of an examinee 120.
As described in Japanese Patent Application Laid-Open Publication No. 2005-193066, since the swallowed capsule endoscope 100 is configured such that the position detection means 108 installed thereinside reacts to the external body plate 109 thereby detecting the position of the capsule endoscope 100 itself, the external body plate 109 is disposed at, for example, a position corresponding to the esophagus 121 of the examinee as shown in FIG. 13. As a result of this, the position detection means 108 of the capsule endoscope 100 senses the external body plate 109 only when the capsule endoscope 100 is present below (near) the external body plate 109.
In this case, the capsule endoscope 100 judges that the capsule endoscope 100 itself is present in the esophagus 121 while the position detection means 108 inside the capsule main body 99 senses the external body plate 109. Thus, since the passing speed of the capsule endoscope 100 will be high when the capsule endoscope 100 is present in the esophagus 121, a photographing apparatus which includes an image pickup device 101 and illumination means 102, etc. operates so that more images are captured by the capsule endoscope 100.
On the other hand, when the position detection means 108 of the capsule endoscope 100 comes not to sense the external body plate 109, it is configured to judge that the capsule endoscope 100 has passed the esophagus 121 and the above described photographing apparatus operates so as to decrease the frame rate.
Therefore, as a result of being configured in this way, the capsule endoscope 100 described in Japanese Patent Application Laid-Open Publication No. 2005-193066 can control the frame rate depending on the site to be observed.